Bicelle-Bicelle lamellar stacking of a fatty alcohol and a C8–10 alkyl PolyGlycoside surfactant

Bio-based surfactants, such as alkyl polyglucosides (APG), exhibit non-classical surfactant behavior due to their sugar-based hydrophilic head groups. The self-assembly behavior of Triton CG110 (C8 alkyl chain APG) was examined in the presence and absence of 1-dodecanol (C 12 OH) using small-angle X-ray and neutron scattering (SAXS and SANS). These techniques allowed for the characterization of aggregate structures and the determination of phase transitions as a function of surfactant concentration and composition. SAXS and SANS analyses revealed that Triton CG110 alone forms bicelles in water. Upon addition of C 12 OH, mixed bicelles were observed at low concentrations, indicating co-assembly of the two surfactants. At higher surfactant concentrations, maintaining a fixed Triton CG110:C 12 OH ratio, a bicelle-to-lamellar transition occurred due to bicelle stacking, while the common lamellar packing adopts a mixed lamellar stacking, where different molecules integrate within the lamellar arrangement. These structural transitions explain the observed non-linear rheological behavior and suggest potential applications for Triton CG110 in systems requiring tailored mesophase structures. • Co-surfactant C 12 OH influences Triton CG110 self-assembly in water. • C 12 OH promotes mixed bicelle formation and modulates phase transitions. • A bicelle-to-lamellar transition occurs at higher surfactant concentrations. • Structural transitions explain non-linear rheology in the bio-based formulation. • Findings enable tailored mesophase design for advanced applications.